My suspicion is that 'Cooper' was a man named Melvin Luther Wilson. Obviously just a personal suspicion, but I came to this view because it seemed given the time that had passed without the crime being solved that Cooper had either left the country or had perished in the descent (or a short time later either because of injuries sustained in the descent or because he was lost in the outdoors). Either way, I felt there was a good chance this person hadn't contacted their family since the hijacking and thought, well, maybe they're listed as a missing person.
So I did a NAMUS search for something like Caucasian men between 5'8 and 6'4, with a current age of between 78 and 108 (and so a generous age range of between 30 and 60 in 1971) whose date of last contact occurred prior to the 25th of November, 1971. I cannot remember if I limited it to people with brown or black hair, or if I left that out to allow for the possibility Cooper had dyed his hair. At any rate, without the hair color specified in the search terms and ordered chronologically oldest to newest, Melvin Luther Wilson is the second result (the circumstances of the first result, a man by the name of Kenneth Michael Plaisted, unfortunately seem to me to strongly suggest foul play rather than anything else - although of course, until things are solved, anything is
possible...) With the hair color specified, Melvin Luther Wilson is the first result. His NAMUS profile is
here.
Reading his NAMUS profile made me wonder why this hadn't been solved yet, he seemed a very strong possibility at first blush. So I googled his name to see if there were any results regarding speculation that he was DB Cooper. I did hit on a few mentions of him in some news articles, mostly those mentions seemed to be linked to his daughter Vicki trying to raise the possibility he is DB Cooper in the media. I believe she may have tried to do this at the time to raise his profile in the public so that the FBI might investigate him more fully, but I do not know. He is discussed on DB Cooper forums. Vicki gives a good summary of some of the things that suggest Melvin Luther Wilson as a good candidate for DB Cooper
here - it is a copy of an email she sent to an FBI agent whom she spoke with in 2011.
Anyway, I was surprised he isn't mentioned in the WS DB Cooper thread. He has a very short thread on WS
here and I was surprised DB Cooper isn't mentioned on it either. You can find links to a video with film footage of him in a link there and a video of a segment from Unsolved Mysteries about him. He was the subject of a Lost Loves segment (I believe at the time of that segment his daughter Vicki, and some of his other children, were seeking to find him as well as to find any other half siblings they might have - it was only at a later date that his daughter Vicki heard about the DB Cooper case and began to suspect that her father might be DB Cooper).
The Unsolved Mysteries segment certainly paints a picture of a man who is capable of undertaking high risk illegal activities in order to get money and also willing to take fairly extreme measures to avoid prosecution for his criminal behavior (in the past doing things like deserting his family and relocating, switching his MO from fraud to counterfeiting). At the time of his disappearance, he was going to face counterfeiting charges in Federal court. He had previously spent several stints in prison is my understanding and, as the Unsolved Mysteries segment explains, was facing up to 25 years if convicted. He is still a wanted fugitive.
Soooo it isn't a stretch for me to think he changed MO again and escalated to a slightly more desperate or risky scheme to obtain money, while also at the same time relocating/fleeing again to start a new life and avoid prosecution. He had military service (naval?) in his background but I do not believe his daughter was able to tell from his military records whether he was a paratrooper (I got lots of this information from her comment
here). I don't know if he was familiar with the area, but he left his home in Minnesota over two months before the hijacking and he was familiar with areas of California and Nevada. It is conceivable to me he was hiding out somewhere around the East coast while he planned this hijacking.
Personally, I feel his appearance is pretty close as well, particularly his manner of dress. Keeping in mind that composite sketches aren't photographs, he is more similar to some of the sketches than he is to others. He is noticeably heavier looking in available photographs than the thinner faced, black and white FBI sketch. He was on the run for over two months, potentially trying to prepare for a hijacking, so it is possible that he may have dropped a couple of pounds because of those things. Vicki does also mention in the comment I linked above that the man sitting across from DB Cooper apparently felt that particular sketch portrayed the man as thinner than the man he saw. I don't know, I didn't see him. To my mind Melvin looks similar to the later, color FBI sketches and to
this sketch that was apparently released by the FBI around 1988 but the providence of which I don't actually know (sorry). But even with weight loss I feel he would still not look exactly like the earlier, thinner sketch (a sketch is still just a sketch, though).
Also, Wilson's DNA or his children's DNA is on file on Namus at least, which throws some doubt on the whole thing. But apparently in 2011 when Vicki's LE/Namus/DOJ contact requested that the FBI run a comparison between Wilson's DNA and DB Cooper samples, the response was an odd sort of side-stepping of the question without confirming or denying whether any DNA comparison had been run or not. In 2015 she still had no idea whether they had actually looked at the DNA to rule him in or out. I got that info from the last two paragraphs
here. My understanding is they only have a partial profile that can only exclude or 'not exclude' but not actually match suspects. So there are three possibilities: they have never compared the partial profile to Melvin's profile (they did, after all, stop active investigation of the DB Cooper case in 2016 to dedicate resources to other cases and it is certainly possible that they were not using many resources on the case in the years leading up to 2016 either), they have compared them and he was excluded without that information being given to his daughter, or they have compared them and he was not excluded but no conclusive match can be made. All three possibilities seem almost equally plausible to me.
It is also of course possible 'Cooper' did get back in touch with his family after the hijacking, or they were aware of his plans and so didn't report him missing, or he had no close or living family to report him missing, or he was never reported missing for other a variety of other reasons, and so my initial approach to the case was the wrong approach anyway. But with the information I have at this time, my gut tells me Wilson is a really strong contender for being DB Cooper.